I have a homeserver in my flat. The local area network is fast ethernet and an external harddrive is connected to the server via USB 2.0. What is the bottle neck when copying files over the network? USB or LAN? I just wanna know, because if the network itself is the slowest part, then I am going to upgrade to gigabit ethernet.

2 Answers 2


The bottleneck is the physical drive inside the external enclosure. USB and Fast Ethernet have theoretical transfer speed faster than your average 5400 RPM spinning disk can write/read.

  • My harddrive also supports USB 3.0. Maybe I should upgrade my server.
    – booman
    Nov 14, 2011 at 18:59
  • No, you aren't understanding what I'm saying. The actual physical spinning disk is the slowest component in the system. USB 2.0 can theoretically transfer 480 Mb/s, FAST Ethernet can theoretically transfer 100 Mb/s, but the physical hard disk is probably going to be somewhere below 100 Mb/s write/read throughput. This means that upgrading your USB to 3.0, or your network to gigabit, will make no difference at all in your performance. The disk is the bottleneck. Nov 14, 2011 at 19:20
  • 2
    NAK. Modern hard drives have high data rates, even 5400 RPM drives, because of high data densities on the platters.
    – Turbo J
    Nov 14, 2011 at 21:49

Lets see:

  • Hard drive: 50-100 MByte/s (recent 1 TB or bigger). Smaller 2,5" is not much slower nowdays.
  • USB2 mass storage: 30-35 MByte/s maximum.
  • Fast Ethernet: 11 MByte/s maximum.

Conclusion: Fast Ethernet is the bottleneck in theory. Upgrading to Gigabit may help a bit, if your homeserver - and the client of course - has a Gigabit interface, but YMMV.

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